Consensus generation of a minimum set of outcome measures for auditing glaucoma surgery outcomes—a Delphi exercise

Purpose To identify the key set of glaucoma surgery outcome measures considered most important and practical to collect by glaucoma specialists. Methods One hundred two glaucoma specialists (57 members of the UK and Eire Glaucoma Society (UKEGS) and 45 members of the European Glaucoma society (EGS)) took part in an Online Delphi exercise. The RAND/UCLA appropriateness method was used analyse data from each round and generate a disagreement index. Results Participants agreed on 13 baseline data points and 12 outcomes that were considered important and practical to collect. For intraocular pressure (IOP) percentage reduction in IOP from baseline (last three IOP readings pre-op) and reduction below a specified target were considered important. For visual fields, change in a global visual field index, e.g. MD, and development of progression as assessed by linear regression were considered important. From a safety perspective, any visual loss resulting in a doubling of the minimal angle of resolution, loss of 5 dB or more of visual field or development of advanced field loss (Hodapp Parrish Anderson Stage 4) was considered important. The importance of routinely using patient reported outcome measures (PROMs) was highlighted. Consensus suggested that outcomes of glaucoma treatments should be reported at 1, 5 and 10 years. Conclusions There was broad consensus on a minimum dataset for reporting the outcomes of glaucoma surgery and outcome measurement intervals.